Cam for lamp-socket keys.



e. B. THOMAS. j

cm ron LAMP SOCKET-KEYS. APPLICATION FILED DEO..18, 1907.

w'xTNsssEs iNvEN-ron 2M@ A 4 f ATToRmrs A i i the tumbler orcam'C, carried by the spin- .UNrrEDf-s'rarns Parser ceram.

c.. nzcE B. THOMAS, OBRIDGEPORT, coNNEc'rioU'r, ASSIGNOR 'ro 'run BRYAN-*ritruo'ruit cQMPnNX, 0F BRIDGEPORT, CONNECTICUT, ooRPoufVrioI-t' or ooNN'n'cfrioUT.

' i .CAM FonLAMP-socrm'r KEYS.

Specification ofiLetters Patent.

j Patented Feb. 23, 1909.

'A p'plcationiled December 18, 19097. Seriall No. $01,073.

"sidingin'Bridgeporhin the county of Fairte1d,in thev State .of Connecticut, have 1n'- -v'enteda certain new anduseful lm proved Gain to'cLamp-Socket Keys, of which the following v1s a specific-anon.

'in thejkeysor switches of electric incan!l descent lamp sockets, receptacles, or the like, a ,rotary cam piece is commonly used to control-the'makl ng andbreaking of the electric circuit. .Heretofore this cam piece has been made of a vpiece stamped or punched from a metal bar,but in practice'it 'is found that unless the temper of the bar is just right, the cam is liableto break. I avoid 4this diiculty and at the same time make the construction cheaper byc'onstructing the cam of a drawn sheet `metal cup.

In the accompanying drawings Figure 1 is a 'erspective View of a lamp socket key provided with my improvement; Figs; 2, 3-

and 4 aresections on the lines Q- Fig. 3, :if-3 and/44, FigQQ respectively with the spindle A vhowever shown in full.

A is the rotary spindle provided with-the usual thumb piece B, and turning in bearings in the yoke D, which latter carries a bent springs, 'acting at its free end upon die At. This cam, when .in the position Ishown in 'Fig'. 1, makes electrical connection between theyoke Dand the threaded lamp shell. the latter not being'shown. `When turned to 'a position at right angles to that `shown, the circuitv i's broken in the usual manner.

cup, (Fig. 2). i -Which lies Within the cupare formed two As shown in the drawing, l forni the cam 4C, by drawing'it up into a cup shape out of sheet metal. The Outlineo'tl the cup is oblong, (Figs. l ant 3), but contracted at the center, where the .spindle A passes through it and through a hole in the bottom of the On that part of the spindle opposite projections a, a, andthe contracted part of the cup is of such relative size that the spindle can turn independently of' the cup within it to a limited extentto provide the required amount of lost motion, but the projections a then come into contact with the side Walls of the cup to turn the cam.

A cam piece thus drawn up into cup shape has been .found to be very strong, not liable to break, and yet cheap to manufacture, and the side walls of the cup provide the necessary strips for the projections on the spindle to turn the cam with lost motion.

I cla-.im as myinvention- -The combination of the key spindle of a lamp socket having projections with a cup shaped cam of .sheet metal drawnup into oblong outline and having indented sides between which the portion ofthe spindle bcaring said projections is located, substantially as described.

In testimony' whereof l have signed my name to this specification.l in the presence of two subscribing witnesses.

GEORGE B. THOMAS.

lVitnesses:

(il. lV. Goomupun, ll'. lV. (ionnsnoutniml. 

